Make function signature be an H1 element

Closes #923

Author: eksperimental

assets/less/content/functions.less

@@ -33,6 +33,7 @@
   }
 
   .signature {
+    font-family: @monoFontFamily;
     font-size: 1rem;
     font-weight: 700;
   }

assets/less/content/general.less

@@ -16,6 +16,10 @@ h1 {
   font-size: 2em;
   margin: 1em 0 .5em;
 
+  &.signature {
+    margin: 0;
+  }
+
   &.section-heading {
     margin: 1.5em 0 .5em;
   }